The present invention relates, generally, to a method and apparatus for separating excavated materials and, more particularly, to a method and apparatus for separating excavated material which utilizes a releasable and interchangeable screen element which is positioned on top of, and releasably engaged to, a frame. Although particularly suited for the separation and recycling of excavated material, the method and apparatus of the present invention may also be used to separate a variety of other materials which comprise some elements that can pass through the releasable screen element. The releasable screen element may be configured of various different screen size openings as well as overall sizes thereby creating a plurality of releasable screen elements which can be easily interchanged with one another on top of the frame.
The separation of excavated material into usable types of material such as, for example, sand, gravel and rock, has been performed by utilizing a number of methods and apparatus. For example, the material separating method and apparatus shown in U.S. Pat. No. 5,244,098 discloses a frame having a tall end and a short end, a vibrating separating screen as a separating surface within the frame, and a fixed angle feed directing plate which functions as a funneling surface to direct feed material into the separating surface at the tall end of the frame. Another example is shown in U.S. Pat. No. 4,197,194 which describes a portable loam screening apparatus which includes a generally square shaped shaker screen supported by a box-like frame having a tall end and a short end. When coarse material is dumped onto the shaker screen, the coarse material falls from the lower end of the shaker screen outside the frame while the loam passes through the shaker screen to within the box-like frame.
Other examples of separating methods and devices are shown in U.S. Pat. Nos. 3,307,698, 4,960,510 and 5,100,539. U.S. Pat. No. 3,307,698 discloses a portable oscillating rock separator having an inverted pyramidical hopper and a sloping grid covering the hopper. Although the sloping grid includes a series of parallel longitudinal rails that are positioned and assembled by a journal tube and a cross plate, the screen is not disclosed as being removable.
U.S. Pat. No. 5,100,539 describes a dual screen apparatus and method for sizing and separating particles of a material. The apparatus includes a stand and a frame with suspension assemblies attached to the stand and the frame for movably suspending the frame on the stand. Further, a pair of inclined screens are removably mounted in a pair of screen boxes which are removably mounted on the frame such that each of the screens slopes downwardly from an intermediate portion of the frame toward an end of the frame. A motor is also mounted on the frame for vibrating for vibrating the frame and the attached screens. Although both the screen boxes and inclined screens are removably mounted, neither of these elements includes a feature for aiding in the positioning and removal of the elements within and from their respective locations within the apparatus.
U.S. Pat. No. 4,960,510 discloses a screening apparatus having a screen grid with a plurality of exchangeable screen elements. The screening apparatus includes a screen grid where sieve elements directly contact one another at the top side of their surfaces to provide a continuous surface having sieve openings and separators or retaining bars are present on their undersides for removably boshing the screen elements to the carrier framework. This apparatus functions to make the active sifting surface of the screen grid in a screening apparatus as large as possible by incorporating the marginal resting areas of the screen elements into the acting sifting surface and to avoid protruding attachment elements on the top side of the screen surface.
Although screen elements or screen grids shown in the prior art are described as being removable and often exchangeable, none of the screen grids or screen elements include means for assisting in the placement and removal of the screen grids or screen elements within the separating apparatus. Accordingly, many of the prior art separating devices must utilize more than one person to position and remove the screen grid or screen element from that area of the separating apparatus where the screen resides, this area typically being the frame of the separating apparatus. Often times, different screen sizes are used to separate and recycle different types of material. Therefore, there is a need for a separating apparatus which enables the easy placement and removal of removable screen grids or screen elements within and out of the separating apparatus. Therefore, there is also a need for a removable screen assembly for utilization within a separating apparatus which includes elements specifically provided to enable the quick and easy placement and removal of the screen assembly or interchangeable screen assemblies which comprises part of the separating apparatus.
A separating method and apparatus are provided which enable the efficient and easy removal of a screen assembly, or interchangeable screen assemblies, that are utilized within the separating apparatus for separating materials from one another.
In accordance with one aspect of the present invention, a separating apparatus for classifying and recycling material is provided which includes a frame member having a slanted grate which has two opposite sides and two opposite ends and a removable screen member positioned on the top surface of the frame member where the removable screen member includes at least one inverted hook member extending from the top surface of the screen member. The slanted grate preferably forms less than a ninety degree angle relative to a ground surface upon which the frame is placed. The inverted hook member or members may be positioned on one or more bar members which extend across the top surface of the screen member and are preferably irremovably secured to one or more of the bar members. These inverted hook members are then easily engaged by the edge of a loader/backhoe bucket so that the operator of the loader/backhoe can easily place and remove the screen member on the frame without the need for additional manpower or equipment. To enable engagement by a loader/backhoe bucket, the bar members containing the inverted hook(s) may comprise a number of configurations, one of the simplest comprising one bar member which horizontally traverses the top surface of the screen member and two inverted hook members spaced equidistantly from one another on the top side of the bar member. Another simple configuration may include two bar members which vertically traverse the top surface of the screen member where one inverted hook is secured to the top surface of each of the bar members such that the inverted hook members are positioned directly across from one another.
In accordance with another aspect of the present invention, the frame member having a slanted grate is provided with at least one flange extending from a bottom side of the slanted grate thereby enabling a loader/backhoe bucket to transport and move the entire frame member by engaging the flange(s). More specifically, the loader/backhoe bucket contacts the bottom side of the slanted grate from the rear of the frame member such that the flange(s) are positioned within the interior of the bucket and adjacent to the outer edge of the bucket. The bucket is then raised and the flange(s) positioned adjacent to the outer surface of the bucket to prevent the frame from slipping off of the bucket when the frame is raised from the ground. The frame member can then be transported to the next desired location.
In accordance with still another aspect of the present invention, a portable screen element is provided which includes a screen member having two opposite sides, two opposite ends, and top and bottom surfaces and at least one bar member traversing the top surface of the screen member where the bar member includes at least one inverted hook member secured to its top surface. Further, as previously described above, the bar member(s) and inverted hook member(s) contained in the screen element may comprise a number of different configurations including the two simplest configurations described above.
In accordance with yet another aspect of the present invention, a method for separating and recycling material is provided which includes the steps of positioning a frame member having a slanted grate relative to a ground surface on the ground, placing a removable screen over the top of the slanted grate by engaging hooks extending from the top of the removable screen with a vehicle or apparatus capable of moving the removable screen, and depositing material to be separated on the top surface of the screen so that the material is separated by passing through both the screen and the grate, both of which are slanted toward the ground relative to the ground surface.
It is a principal object of the present invention to provide an efficient and easy method and apparatus for placing and removing removable screen assemblies contained within a separating apparatus. Achieving this objective eliminates the requirement for tools and extra manpower in removing and changing the screen assembly. As a result, a single equipment operator can easily use the loader/backhoe bucket to carry out the placement and removal of the screen assembly.
Various other aspects and advantages of the present invention are set forth with particularity in the detailed description of exemplary embodiments of the invention.